Silver handle emulsion and silver halide photographic lightsensitive material

Abstract

A silver halide emulsion comprises an electron-releasing compound of Types 1 to 4: (Type 1) a compound capable of undergoing a one-electron oxidation (1-EO) to form a one-electron oxidation product (1-EOP), the 1-EOP capable of releasing further two or more electrons accompanying a subsequent bond cleavage reaction, (Type 2) a compound capable of undergoing 1-EO to form 1-EOP, the 1-EOP capable of releasing further one electron accompanying a subsequent bond cleavage reaction, and having, in its molecule, two or more adsorptive groups acting on silver halides, (Type 3) a compound capable of undergoing 1-EO to thereby form 1-EOP, the 1-EOP capable of releasing further one or more electrons after going through a subsequent bond forming process, and (Type 4) a compound capable of undergoing 1-EO to form 1-EOP, the 1-EOP capable of releasing further one or more electrons after going through a subsequent intramolecular ring cleavage reaction.

What is claimed is:  
     
       1. A silver halide emulsion comprising at least one compound selected from the following four types of electron-releasing compounds, namely: 
       (Type 1) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further two or more electrons accompanying a subsequent bond cleavage reaction;  
       (Type 2) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further one electron accompanying a subsequent bond cleavage reaction, and the one-electron oxidation product having, in its molecule, two or more adsorptive groups acting on silver halides;  
       (Type 3) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further one or more electrons after going through a subsequent bond forming process; and  
       (Type 4) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further one or more electrons after going through a subsequent intramolecular ring cleavage reaction.  
     
     
       2. The silver halide emulsion according to  claim 1 , wherein said at least one compound is a compound which undergoes a one-electron oxidation induced by exposure of the silver halide emulsion to light. 
     
     
       3. The silver halide emulsion according to  claim 1 , wherein said at least one compound is represented by any of the following general formulae (A), (B), (C), (D), (E), (F), (1), (2) and (3):                    
       wherein in the general formula (A), RED 11  represents a one-electron oxidizable reducing group; L 11 , represents a split-off group; R 112  represents a hydrogen atom or substituent; and R 111  represents a nonmetallic atomic group capable of forming a cyclic structure corresponding to a tetrahydro form, hexahydro form or octahydro form of a 5-membered or 6-membered aromatic ring (including an aromatic heterocycle) together with carbon atom (C) and RED 11 ;  
       in the general formula (B), RED 12  and L 12  have the same meanings as those of RED 11  and L 11  of the general formula (A), respectively; each of R 121  and R 122  represents a hydrogen atom or substituernt; and ED 12  represents an electron-donating group; in the general formula (B), R 121  and RED 12 , or R 121  and R 122 , or ED 12  and RED 12  may be bonded with each other to thereby form a cyclic structure;  
       in the general formula (C), RED 2  has the same meaning as that of RED 12  of the general formula (B); L 2  represents a split-off group; each of R 21  and R 22  represents a hydrogen atom or substituent; and RED 2  and R 21  may be bonded with each other to thereby form a cyclic structure; the compound represented by the general formula (C) is a compound having, in its molecule, two or more adsorptive groups acting on silver halides;  
       in the general formula (D), RED 3  has the same meaning as that of RED 12  of the general formula (B); Y 3  represents a reactive group capable of reacting with a one-electron oxidation product formed as a result of a one-electron oxidation of RED 3  to thereby form a new bond; and L 3  represents a linking group which links between RED 3  and Y 3 ;  
       in the general formulae (E) and (F), each of RED 41  and RED 42  has the same meaning as that of RED 12  of the general formula (B); and each of R 40  to R 44  and R 45  to R 49  represents a hydrogen atom or substituent. In the general formula (F), Z 42  represents —CR 420 R 421 —, —NR 423 — or —O—; herein, each of R 420  and R 421  represents a hydrogen atom or substituent; and R 423  represents a hydrogen atom, alkyl group, aryl group or heterocyclic group;  
       in the general formula (1), Z 1  represents an atomic group capable of forming a 6-membered ring together with the nitrogen atom and the two carbon atoms of the benzene ring; each of R 1 , R 2  and R N1  represents a hydrogen atom or substituent; X 1  represents a group capable of substituting on the benzene ring; m 1  is an integer of 0 to 3; and L 1  represents a split-off group;  
       in the general formula (2), ED 21  represents an electron-donating group; each of R 11 , R 12 , R N21 , R 13  and R 14  represents a hydrogen atom or substituent; X 21  represents a substituent; m 21  is an integer of 0 to 3; and L 21  represents a split-off group, wherein any two of R N21 , R 13 , R 14 , X 21  and ED 21  may be bonded with each other to thereby form a cyclic structure; and  
       in the general formula (3), each of R 31 , R 32 , R 33 , R N31 , R a  and R b  represents a hydrogen atom or substituent; and L 31  represents a split-off group, provided that, when R N31  represents a group other than an aryl group, R a  and R b  are bonded to each other to thereby form an aromatic ring.  
     
     
       4. The silver halide emulsion according to  claim 1 , wherein said electron-releasing compounds of types 1, 3 and 4 are compounds each having in its molecule at least one adsorptive group acting on silver halides or at least one partial structure of a spectral sensitizing dye. 
     
     
       5. The silver halide emulsion according to  claim 1 , wherein each of said compounds is a compound having in its molecule two or more mercapto groups as a partial structure thereof. 
     
     
       6. The silver halide emulsion according to  claim 1 , wherein each of said compounds has a nitrogen-containing heterocyclic group that is substituted with two or more mercapto groups, as the adsorptive group. 
     
     
       7. The silver halide emulsion according  claim 3 , wherein said split-off group of each of the general formulas (A) to (F) and (1) to (3) is a carboxyl group or salt thereof, or hydrogen atom. 
     
     
       8. The silver halide emulsion according to  claim 3 , wherein said compound of general formula (D) is represented by any of the following general formulae (D-1) to (D-4):                    
       wherein in the general formulae (D-1) to (D-4), each of A 100 , A 200 , A 300  and A 400  represents an aryl group or a heterocyclic group, provided that each of A 100 , A 200  and A 400  represents a divalent group resulting from removal of one hydrogen atom from an aryl group or a heterocyclic group; each of L 301 , L 302 , L 303  and L 304  represents a linking group; each of Y 100 , Y 200 , Y 300  and Y 400  represents a reactive group; each of R 3100 , R 3110 , R 3200 , R 3210  and R 3310  represents a hydrogen atom or substituent, wherein R 3110  and A 100 , or R 3210  and A 200 , or R 3310  and A 300  may be bonded with each other to thereby form a cyclic structure; and X 400  represents a hydroxyl group, mercapto group or alkylthio group.  
     
     
       9. The silver halide emulsion according to  claim 1 , wherein an oxidation potential with respect to said first electron is 0 V or more and 1.4 V or less. 
     
     
       10. The silver halide emulsion according  claim 1 , wherein said one-electron oxidation product that is produced after said one-electron oxidation of said compounds of Types 1 to 4 has an oxidation potential of −0.7 V or less. 
     
     
       11. The silver halide emulsion according to  claim 1 , wherein silver halide grains contained in said silver halide emulsion comprise tabular grains having an aspect ratio of 5 or more. 
     
     
       12. A silver halide emulsion having been chemically sensitized by at least one compound selected from the following four types of electron-releasing compounds: 
       (Type 1) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further two or more electrons accompanying a subsequent bond cleavage reaction;  
       (Type 2) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further one electron accompanying a subsequent bond cleavage reaction, and the one-electron oxidation product having, in its molecule, two or more adsorptive groups acting on silver halides;  
       (Type 3) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further one or more electrons after going through a subsequent bond forming process; and  
       (Type 4) an electron-releasing compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, the one-electron oxidation product capable of releasing further one or more electrons after going through a subsequent intramolecular ring cleavage reaction.  
     
     
       13. A silver halide photographic lightsensitive material comprising said silver halide emulsion according to  claim 1 . 
     
     
       14. The silver halide photographic lightsensitive material according to  claim 13 , wherein said silver halide emulsion is chemically sensitized by at least one compound selected from said electron-releasing compounds of Types 1 to 4. 
     
     
       15. The silver halide photographic lightsensitive material according to  claim 13 , further comprising at least one reducing compound. 
     
     
       16. The silver halide photographic lightsensitive material according to  claim 14 , further comprising at least one reducing compound.